Antiknock gasoline compositions



3,000,709 ANTIKNOCK GASQLINE COMPOSITIONS Harold D. Orlofi, Oak Park, and James B. Hinkamp, Birmingham, Mich, assignors to Ethyl Corporation, New York, N .Y., a corporation of Delaware No Drawing. Filed Oct. 24, 1956, Ser. No. 617,927 4 Claims. ((31. 44-63) This invention relates to improved liquid fuel for internal combustion engines and to composite additives for such fuel.

Erratic ignition produced by glowing engine deposits is a severe problem in spark ignition internal combustion engine operation. This phenomenon known as surface ignition manifests itself in reduced efiiciency of operation, loss of power and of fuel economy and in increased wear of engine parts.

A critical limitation imposed upon any additive to be used in controlling surface ignition in engines is that it must not destroy the antiknock elfectiveness of the alkyllead antiknock material with which it is employed. Failme to meet this limitation causes, among other things, loss of gasoline octane quality, a property which is needed in these days of the high compression engine.

An object of this invention is to provide composite additives for spark ignition internal combustion engine fuels capable of substantially reducing surface ignition without causing loss of antiknock effectiveness. Another object is to provide improved liquid fuel for spark ignition internal combustion engines having the above properties. Other objects of this invention will be apparent from the ensuing description.

The above and other objects are accomplished by providing an antiknock composition adapted for use as an additive for spark ignition internal combustion engine fuel comprising an alkyllead antiknock compound, and, in amount sufi'icient to reduce surface ignition, a cyclic phosphorus compound having the general formula wherein R is selected from the group consisting of amino, monoalkyl amino groups in which the alkyl portion contains from 1 to 2 carbon atoms, dialkyl amino groups in which each of the alkyl portions contains from 1 to 2 carbon atoms, methoxy, phenoxy groups containing from 6 to carbon atoms, and having only aromatic unsaturation and chlorophenoxy groups containing from 6 to 10 carbon atoms and from 1 to 2 chlorine atoms and having only aromatic unsaturation; R and R are selected from the group consisting of hydrogen and methyl; and R and R are selected from the group consisting of hydrogen, methyl and ethyl. Such antiknock compositions preferably contain a scavenger complement, althoughthis is not essential to the present invention since our scavengerfree leaded fuels may be used in special applications, such as in break-in schedules of engines and in experimental studies of engine behavior. In all such special applications, the normal detrimental surface ignition rate is virtually eliminated by our scavenger-free fuels. Furthermore, the combination of an alkyllead antiknock agent the above alkyllead antiknock compositions are blended in antiknock quantities with liquid hydrocarbon fuel of the gasoline boiling range. Amounts of lead from about- 0.02 to about 6.5 grams of lead per gallon can be used. Higher concentrations of alkyllead antiknock compounds may be used, such as in the preparation of gasoline-type fuels for the above special applications and in the preparation of concentrated leaded gasoline solutions which are diluted during blending operations to prepared finished fuels of this invention.

The amount of the above cyclic phosphorus compounds used in the compositions of this invention is from about 0.05 to about 0.8 theory of phosphorus, a theory of phosphorus being the quantity required to react with the lead to form lead orthophosphate, i.e., 2 atoms of phosphorus per each 3 atoms of lead. In other words, the amount of cyclic phosphorus compounds so used is such that the phosphorus-to-lead atom'ratio is from about 0.123 to about 1.6:3. Greater or lesser amounts of the cyclic phosphorus compound may be employed depending upon such factors as the type of engine operation to be incurred, the octane quality of the fuel used, and the like. Best over-all results are achieved from compositions of this invention which contain the above-defined cyclic phosphorus compounds in amounts such that the phosphorus-to-lead atom ratio is from about 0.4:3 to about 1:3. Such amounts are preferred.

The compositions of this invention are capable of (1) obviating ordinary knock, (2) substantially reducing surface ignition and (3) alleviating spark plug fouling, because of the cooperation between the alkyllead and cyclic phosphorus ingredients. Moreover, these improved benefits are obtained with virtually no loss in antiknock effectiveness of the alkyllead ingredient.

Among the features of the cyclic phosphorus compounds employed according to this invention is that theirchemical structure is important in contributing to. the enhanced deposit-modifying characteristics provided.

To prepare the improved composite additives of this invention the desired proportions of the ingredients are placed in a suitable container, such as a blending tank,

and mixed. To insure homogeneity, use is made of conventional methods of physical agitation, such as stirring, shaking or the like. The order of addition of the ingredients during formulation is not critical. Thus, an alkyllead compound may be added to a cyclic phosphorus compound, a cyclic phosphorus compound may be added to an alkyllead compound, or these ingredients may be introduced into the blending apparatus concurrently,

When a scavenger complement is employed, it can be added to an alkyllead-cyclic phosphorus compound blend which has been performed as described above or the 1 scavenger complement can be introduced into the blenderconcurrently with the other ingredients. However, it is 5 desirable to take advantage of the enhanced solubility of the above cyclic phosphorus compounds in or in the presence of scavengers and therebyreduce the time of the blending operation. This can be done by dissolving the cyclic phosphorus compound in the scavenger and blend Patented Sept. 19, 1961,

ing this solution with an alkyllead compound, or by adding the cyclic phosphorus compound to a preformed mixture of an alkyllead compound and scavenger. The same blending procedures can be used when other ingredients are to be incorporated into the composite additives of this invention.

Representative alkyllead antiknock compositions of this inventioni.e., composite additives-are represented in Table I. The figures following the representative ingredients are parts by weight. The two figures following the cyclic phosphorus ingredient show respectively the amounts which are used to obtain a composition having a phosphorus-to-lea'd atom ratio of 0.123 and 1.623. It the lower figure is doubled, the resulting composition will have a phosphorus to-lea'd atom ratio of 0.213, whereas one fourth of the second figure provides a composition having a phosphoru's' to-lead atom-ratio of 0.4:3. For other phosphorus concentrations, the proper adjustments are evident.

Table I'-A ntzknock fluid compositions Antiknock Scavenger Cyclic phosphorus additive agent Tetramethyl None 1,3-butylene-phosphoramidate lead 267. fill-80.5..

Do Ethylene dibromide 1,3 propylene (3,5 dimethyl 226. phenyDphosphate 8.1129.1.

Do Ethylene dibromide 2, 2-dhnethyl-1,3-propylene-(N 94 and ethylene cllmethyl) -phosphoramidate I chloride 99. 6.095.5. Tetraethyl None l,3-amylene-.(methyl) phoslead 323. phate till-96.0.

Do.-.' Ethylene dibromlde 1,3-hutylene-(3,5-dimethyl- 188. phenyl) phosphate 8.84413.

Do Ethylene dibromide 1,3-butylene phosphoramidate 94 and ethylene dl- 5.0-805.

. V chloride 99.

Do Ethylene dibromlde 1,3 propylene (2,4 v dimethyl 113 and ethylene di phenyl) phosphate 8.0-128.5.

. chloride 99.

Do Mixed dlbromotol- 2,2 L dlmethyl 1,3 propylene uenes 200. (N,N-di.methyl) phosphoramidate (EA-102.9.

Do Mixed dihromotol- 1,3 butylene- (2,, 5- dichlorouenes 125 and phenyl) phosphate 99458.4. gghylene dichloride Do Mixed dlbromotol- 4,4 dimethyl 3,5 heptylene nenes 150 and 1,2,4- (N ,N-diethyl) phosphoramitrichlorobenzenes. date Sit-132.8.

Do Ethylene dibromide 1,3-butylene- (2,5- dimethyl-i- 94 and mixed trl ethylphenyl) phosphate 9.5- chlorobenzenes 146. 151.5. g

D0.- 1,4-dibromobutane 3 -methyl-2,6 -hexy1ene phos phoramidate 6.4.1024. Do 1,4-dibromobutane v 1,3 prop ylene-(N-methyl) 108 and 1,4-diehlorophosphoraxnldate 50-805. butane127. Tetrapropyl Acetylene tetrabro 2-methyl-1,3-butylene-(2,5-dilead 379. mide 346. chloro 3,6 diethylphenyl) phosphate 12.2 1955. t, Dlmethyldi- B,B-Dlbromodietliyl 1,3 butylene (mixed xylyl) rzagtlgyl lead other 232. phosphate 8.8-141.3. M'ethyltri- B,B'-D1bron1odii'so 2,2 dimethyl 1,3 propylene ethyl lead propyl ether 130 phosphoramidate 55-881). 309. and 6,8-dichlorodiethyl ether 143.

The antiknock fluid compositions shown in Table I are presented for illustrative purposes only. Other antiknock fluid compositions will now be apparent to one skilled in the an.

A variety of blending procedures are available to prepare the improved fuel compositions of this invention. For example, a composite additive of this invention, such as described in Table I, can be blended in appropriate concentration with a gasoline-type fuel to provide a finished fuel of this invention containing from about 0.02 to about 6.5 grams of lead per gallon. Another method is to add an appropriate concentration of a cyclic phosphorus compound separately to the fuel before, after or at the same time an alkyllead antiknock agent or conven tional alkyllead antiknock fluid composition is blended with the fuel. Still another procedure is to blend with the fuel each of the ingredients of the above composite additives separately or in various suhcombinations in any sequence.

Illustrative improved fuel compositions of this invention are shown in Table II. The two figures following each of the ingredients are weights in grams thereof. By blending each of the ingredients in the amounts of the respective lower figures with 10 gallons of gasoline, a fuel composition of this invention containing 0.5 gram of lead per gallon as the lead alkyl antiknock agent is prepared. The respective figures following each ingredient show the amount in grams thereof which are blended with 10 gallons of gasoline to provide a lead content of 6.5 grams per gallon. These illustrative fuels have a phosphorus-to-lead atom ratio of 04:3. The characteristics of the base fuels represented in Table II as A, B, C and Dare as follows:

Base fuel A.A blend of straight-run, catalyticallycracked and polymer stocks. Initial boiling point, 98 F.; endpoint, 402 F.

Base fuel B. -A 100% catalytically-cracked gasoline having an initial boiling point of F. and an endpoint of 425 F.

Base fuel C.An aviation gasoline of Grade 100/130 comprising isopentane, alkylate, aromatics and straightrun gasolines. Initial boiling point, 82 F.; endpoint, 330 F.

Base fuel D.A blend of light, catalytically-cracked naphtha, polymer stock, catalytic reformate and light, straight-run naphtha containing butane to the proper Reid vapor pressure. Initial boiling point, 90 F.; endpoint, 368 F.

Table II-Antrknock fuel COmPOSUIOIZS Base Antiknock agent Scavenger Oyelie phosphorus fuel Additive A".-. Tetramethyllead Ethylene diehl'o- 1,3-propylene-(2,4,5-

Ssh-83.8. ride 2.4-311. trlniethylphenyl) phosphate [LS-10.7.

A Tetraethyllead Ethylene dibro- 1,3-butylene phosphor- 7 .8-101.4. mide 23-205 amidate 0.6-6.3.

and ethylene gliclhloride 2.4-

B do Ethylene dibro- 1,3-butylene-(3 -chloremide 2.735.4 and 4-rnethylphen'yl) ethylene dichlophosphate 0.911.5. ride 2.t-31.l.

B do Mixed dibromo- 2,2-dimethyl-L3- toluenes 25.6-47.1 propylene-(N,N-- and ethylene didirnethyl) phosphorehloride 2.937.3. amidate.0.912.3;

0 do None 3-methy1-2,4-amylene- (grrieghlyD-phosphate O .d0 1,4-d1brornobutane 1,3-buty1ene-(n-ethyl) 5.2-618. glogpjhoramldate D. Tetrabutyllead Mixed dlbromo- 1,3-butylene-(3,5-di- 10.543615. toluenes 13.0-39.1 chloro-2,6-diethyland 1,2,4-triphenyl) phosphate ehlorobenzene 1.1-14.8.

D. Trimethylethyl- 1,3-dibromopro- 1,3-propylone-(N- lead 6.888.2. pane 2.4-3L7 and methyl) phosphor- B,B-diehlorodiamidate 0. 5-6.3. g tilgyl other 3.5-

To illustrate the great efiectiveness of the compositions of this invention in suppressing surface ignition, recourse was had to engine tests. A spark ignition internal coinbustion engine equipped with an electronic device which automatically recorded surface ignitions was used in the test. This engine was operated on a commercially available gasoline containing about 3.2 grams of lead per gallon as a conventional antiknock mixture (tetraethyllead, about 0.5 theory of bromine as ethylene dibromide and about 1.0 theory of chlorine as ethylene dichloride). This established a baseline in terms of the number of surface ignitions which owurred per hour. Individual portions of the same leaded fuel were then treated with typical phosphorus additives of this invention-LS-butyltehe-(3- methylphenyl) phosphate; 1,3-butylene (N,N-diethyl) phosphoramida'te and l,3-butylene-(3,5-dimethylphenyl)'- phosphate-in amount such that the phosphorus-to-lead atom ratio was about 0.4:3. The engine was then operated on these fuels and the effect of the presence of the phosphorus additives of this invention determined. The results of these experiments are shown in Table 111.

Table III-Efiect of phosphorus additives on surface The results shown above are illustrative of the enhanced surface ignition suppressing properties of the compositions of this invention. Equally good results are obtained with other such compositions, such as those shown in Tables I and H.

Our compositions also effectively alleviate spark plug fouling by beneficially modifying the characteristics of deposits formed on spark plug electrodes and insulators.

Since our cyclic phosphorus additives are highly efiective in reducing surface ignition and spark plug fouling, they may be used at lower concentrations than additives suggested heretofore to obtain the same degree of effectiveness. On the other hand, they may be used at the same or higher concentrations if still greater benefits regarding these problems are desired.

Another outstanding characteristic of our improved antiknock compositions is that in use there is no adverse efiect on the antiknock efiectiveness of the alkyl antiknock agent during the cooperation of this agent and the cyclic phosphorus additives of this invention. This exceptional characteristic of our cyclic phosphorus additives was clearly demonstrated by conducting a series of comparative engine tests. Individual portions of a representative motor gasoline containing about 3.2 grams of lead per gallon as tetraethyl lead as an antiknock fluid comprising tetraethyllead, 0.5 theory of bromine as ethylene dibromide and 1.0. theory of chlorine as ethylene dichlorideeach portion containing a given concentration of phosphorus-were subjected to the standard ASTM Motor Method, Test Procedure D357 (which can be found in the 1953 edition of ASTM Manual of Engine Test Methods for Rating Fuels). In these tests typical additives of this invention1,3-butylene-(3,5-dimethylphenyl) phosphate; 1,3- butylene-(3-methylphenyl) phosphate; 1,3-butylene-(4- chloro 3 methylphenyl) phosphate and 1,3 butylene- N,N-dimethyl) phosphoramidatewere tested at a phosphorus-to-lead atom ratio of 0.4:3. For comparative purposes, tributylphosphite, an additive suggested heretofore, was tested under identical conditions at the same phosphorus-to-lead atom ratio. The results of these engine tests are shown in Table IV.

Table I V-Efiect of phosphorus additives on tetra- The preeminence of the cyclic phosphorus additives of this invention from the standpoint of their compatibility with alkyllead antiknock agents during engine combustion was further demonstrated by conducting another series of engine tests. In this instance, the standard ASTM Re search Method, Test Procedure D-908 (which can be found in the 1953 edition of ASTM Manual of Engine Test Methods for Rating Fuels) was used. The gasoline contained 3.2 grams of lead per gallon as tetraethyllead, 0.5 theory of bromine as ethylene dibromide and 1.0 theory of chlorine as ethylene dichloride. In the present tests the representative additives of this invention used were 1,3-butylene-(3,5-dimethylphenyl) phosphate; 1,3- butylene (3 methylphenyl) phosphate; 1,3 butylene- (N,N-diethyl) phosphor-amidate and 2,2-dimethyl-l,3- propylene-(3-methylphenyl) phosphate. For comparative purposes, tricresyl phosphate and triethyl phosphate were also tested. In all cases the phosphorus-to-lead atom ratio was 0.4:3. The results of these tests are shown in Table V.

Table V-Bfiect of phosphorus additives on tetraethylleaa' antiknock effectiveness Tetraethyllead efiectiveness destroyed, percent Phosphorus additive Additives of the invention:

1,3-butylene-(3,5-dimethylphenyl)-phosphate 0 1,3-butylene(3-methylphenyl) phosphat 1 1,3-butylene-(N,N-diethyl) phosphorainidate 0 2,2-%irtnethyl-1,3-propylene-(3-methylphenyl) phosp a e. 0

Additives not of the invention- 'Iricresyl phosphate 3 Triethyl phosphate 8 in which R through R; are as defined hereinabove, with a compound capable of replacing the phosphorusbonded chlorine atom and creating a bond between the. phosphorus and the appropriate radical of the additives of this invention. Thus, to prepare the cyclic phosphoramidates used according to this invention, the above cyclic phosphorus monochloride is reacted with ammonia, methylamine, dimethylamine, ethylamine, diethylamine or methylethylamine. These primary or secondary alkyl amines or ammonia are added in a -mole percent excess of the amount required to replace the phosphorus-bonded chlorine. Such excess amount acts as an acceptor of hydrogen chloride. This reaction is carried out at a temperature between about 0 to about 50 C. It is desirable to use a suitable solvent, such as diethyl ether, petroleum ether, or the like.

The cyclic phosphate additives used according to this invention are prepared by reacting the above cyclic phosphorus monochloride with sodium methylate, or the sodium salt of a phenol containing from 6 to 10 carbon atoms or of a chlorophenol containing from 6 to 10 carbon atoms and from 1 to 2 chlorine atoms. This reaction is carried out at a temperature between about 20 to about 60 C.

The cyclic phosphorus monochlorides of the above general formula are obtainable by reacting phosphoryl '5 trichloride with a dihydroxy compound having the general formula wherein R and R are selected from the group consisting of hydrogen and methyl and R and R are selected from the group consisting of hydrogen, methyl and ethyl. One mole of dihydroxy compound is used per each mole of the phosphoryl trichloride. The reaction temperature is between about and about C.

Typical cyclic phosphorus compounds as above delined and used according to this invention include 1,3-propylene phosphoramidate; 1,3-propylene-(N-methyl) phosphoramidate; 1,3-propylene-(N-ethyl) phosphoramidate; 1,3-propylene-(N,N-dimethyl) phosphoramidate; 1,3-propylene-(N,N-diethyl)phosphoramidate; 1,3-butylene phosphoramidate; 1,3-butylene-(N-rnet-hyl) phosphoramidate; 1,3-butylene-(N-ethyl) phosphorarnidate; 1,3-butylene-(N,N-dimethyl) phosphoramidate; l,3-butylene-(N,N-diethyl) phosphoramidate; 1,3-butylene-(N-methyl-N-ethyl) phosphoramidate; 2,4-amylene phosphoramidate; 2,4-amylene-(N-ethyl) phosphoramidate; 2,4-amylene-(N,N-diethyi) phosphorarnidate; 1,3-amylene-(N-methyl) phosphoramidate; 1,3-amylene-(N,-N-dimethyl) phosphoramidate; l,3-amylene-(N,N-diethyl) phosphoramidate; 3,5-heptylene phosphoramidate; 3,5-heptylene-( N-ethyl) phosphoramidate; 3,S-heptylene-(N,N-diethyl) phosphoramidate; 2-methyl-1,3-propylene phosphoramidate; 2-methyl-1,3-propylene-(N-ethyl) phosphoramidate; Z-methyl-1,3-propylene-(N,N-diethyl) phosphoramidate; 2,2-dimethyl-1,3-propylene phosphoramidate; 2,2-di-methyl-1,3-propylene-(N-methyl) phosphorarnidate; 2,2-dimethyl-l,3-propylene-(N,N dimethyl) phosphoramidate; 3-rnethyl-2,4-hexylene phosphoramidate; 3,3-dimethyl-2,4-amy-lene phosphoramidate; 3,3-dimethyl-2,4-amylene-(N-ethyl) phosphoramidate; 3,3-dimethyl-2,4-amylene-(N,N-diethyl) phosphoramidate; 1,3-propylene-(methyl) phosphate; 2,2-dimethyl-1,3-propylene-(methyl) phosphate; 1,3-butylene-(phenyl) phosphate; 2,2-dimethyl-1,S-butylene-(4-methylphenyl) phosphate; 2,2-dimethyl-1,3-butylene-(3,5-diethylphenyl) phosphate; 1,3-buty-lene-(4-chlorophenyl) phosphate; 4,4-dimethyl-3,S-heptylene-(3-ethyl-4-chlorophenyl) phosphate; 2,4-amylene-(3,5-dichlorophenyl) phosphate; 3-methyl 2,4 hexylene (3-methyl-4-isopropylphenyl) phosphate; 1,3-butylene-(3-methylphenyl) phosphate; 1,3-butylene-(d-n-butylphenyl) phosphate; l ,3-butylene-(3-ethy1-4-chlorophenyl) phosphate; 1,3-butylene-(methyl) phosphate; 1,3-amylene-(methyl) phosphate; 1,3-amylene-(phenyl) phosphate,

containing from 4 to about 16 carbon atoms, one atom of lead and a plurality of lead-to-carbon bonds, are capable of increasing the octane quality of gasoline when employed therein in antiknock quantities-about 0.02 to about 6.5 grams of lead per gallon. Of such compounds, tetraalkyllead compounds having 4 to about 12 carbon atoms have superior volatility characteristics from the standpoint of engine induction and are the preferred. Halogen-containing-alkyllead compounds, such as, triethyllead bromide may also be used in the compositions of this i ve n-v The scavengers which are preferably but not necessarily present in the compositions of this invention are organic halide compounds which react with the lead during combustion in the engine to form volatile lead halide. The halogen of these scavengers has an atomic weight between 35 and that is, the active scavenging ingredient is chlorine and/or bromine. Such scavengers include ethylene dibrornide; ethylene dichloride; carbon tetrachloride; propylene dibrornide; 2-chloro-2,3-dibromobutane; 1,2,3- tribrornopropane; hexachloropropylene; mixed bromoxylenes; 1,4-dibromobutane; 1,4-dichloropentane; fl,fl'-dibromodiisopropyl ether; p,p'-dichlorodiethyl ether; trichlorobenzene; dibromotoluenes; tert-butyl bromide; Z-methyl- Z-bromobutane; 2,3,3-trimethyl-2-bromobuta ne; tert-butyl chloride; 2,3-dirnethyl-2,S-dibromobutane; 2,3-dimethyl- 2,5-dibromohexane; 2-methyl-2,3-dibromobutane; Z-methyl-2, 3-dichloroheptane; 2methy-l-2,4-dibromohexane; 2,4- dibromopentane; 2,5-dichlorohexane; 3methyl-2,4-dibromopentane; l-phenyl-l-bromoethane; l-phenyH-chloro ethane; ethyl-u-bromoacetate; diethyldibromomalonate; propyl-u-chiorobutyrate; 1,l-dichloro-l-nitroethane; 1,1- dichloro-Z-nitroethane; 1,1-dibromo-l-nitrobutane; 2-chloro-4-nitropentane; 2,4dibromo-3-nitropentane; l-chloro- Z-hydroxyethane; l-bromo-3-hydroxypropane; l-bromo- 3 hydroxybutane; 3-methyl-2-bromo-4-hydroxypentane; 3,4-dimethyl-2 bromo-4-hydroxypentane; and, in general, scavengers disclosed in U.S. Patents 1,592,954; 1,668,022; 2,364,921; 2,479,900; 2,479,901; 2,479,902; 2,479,903; and 2,496,983. In short, it is preferred to employ halo genated scavengers containing only carbon and elements selected from the group consisting of hydrogen, bromine, chlorine, nitrogen and oxygen. Particularly preferred scavengers are halohydrocarbons, that is, bromohydrocarbons, chlorohydrocarbons, and bromochlorohydrocarbons having a vapor pressure from 0.1 to 250 millimeters of mercury at 50 C. The total amount of scavenger used is preferably from about 0.5 to about 2.0 theories, a theory being defined as the quantity required to react with the lead to form lead halide-Le, two atoms of halogen per atom of lead. This amount can be in the form of a single compound or a mixture of compounds. However, when We use mixtures of bromine-containing and chlorine-containing scavengers, particularly broomand chlorohydrocarbons as the scavenger complement, we can employ a wider range of concentrations in the proportions described in US. Patent 2,398,281. Thus, the scavenger concentrations used are those which are suflicient to control the amount of deposits formed in the engine, particularly on the exhaust valves.

The cyclic phosphorus additives of this invention are soluble in alkyllead antiknock compounds, alkyllead antiknock fluids and in gasoline-type fuel in excess of the amount used to impart thereto the improvements of this invention. Thus, additional solvents for these additives are ordinarily unnecessary. Under special conditions, such as when blending is to occur at subzero temperatures or when highly concentrated stock solutions are to be employed in blending operations, a solvent may be advantageously employed. Particularly suitable solvents include acetone, methylethyl ketone, methanol, ethanol, isopropanol, methylisobutylcarbinol, benzene, toluene, xylene, and the like. In general, ketones and alcohols containing up to about 6 carbon atoms and aromatic hydrocarbons containing 6 to 18 carbon atoms are excellent solvents. Formulations of the cyclic phosphorus compounds of this invention using such solvents are also useful in refinery operations where the cyclic phosphorus compound is to be blended into the gasoline apart from 9 the alkyllead antiknock agent or conventional antiknock fluid.

The antiknock compositions of this invention can contain other ingredients, such as dyes for identification purposes; metal deactivators, such as N,N-disalicylidenel,2- diaminopropane, etc.; other antiknock agents, such as the carbonyls of iron, nickel and like elements; aromatic amines, such as N-methylaniline, xylidine, etc.; anti-icing and anti-rust additives; other surface ignition control additives; upper cylinder lubricants; induction system cleanliness agents; antioxidants, such as N,N-di-sec-butyl-pphenylenediamine, p-alkylamino phenols, alkyl phenols, etc. and the like.

Our antiknock fluids may be used in a variety of hydrocarbon base stocks boiling within or throughout the gaso line boiling range. This range is from about 80 toabout 420 F. for motor gasolines, while the endpoint of aviation fuels is in the order of about 310335 F. Thus, improvements can be made in fuels resulting from thermal and catalytic cracking processes, reforming, hydroforming and alkylating procedures; in straight run gasolines; and in various blends of gasoline hydrocarbons.

This application is a continuation-in-part of our prior copending application S.N. 526,318, filed August 3, 1955, and now abandoned.

We claim:

1. A hydrocarbon fuel of the gasoline boiling range adapted for use in spark ignition internal combustion engines containing an antiknock quantity of an alkyllead antiknock compound, said quantity being from about 0.02 to about 6.5 grams of lead per gallon of said fuel and, in amount sufficient to reduce surface ignition, a cyclic pentavalent phosphorus compound having the general formula wherein R is selected from the group consisting of amino, monoalkyl amino groups in which the alkyl portion contains from 1 to 2 carbon atoms, and dialkyl amino groups in which each of the alkyl portions contains from 1 to 2 carbon atoms, R and R are selected from the group consisting of hydrogen and methyl; and R and R are selected from the group consisting of hydrogen, methyl and ethyl.

2. An antiknock composition adapted for use as an additive for spark ignition internal combustion engine fuel consisting essentially of an alkyllead antiknock compound and a cyclic pentavalent phosphorus compound having the general formula Ra H wherein R is selected from the group consisting of amino, monoalkyl amino groups in which the alkyl portion contains from 1 to 2 carbon atoms, and dialkyl amino groups in which each of the alkyl portions contains from 1 to 2 carbon atoms, R and R are selected from the group consisting of hydrogen and methyl; and R and R are selected from the group consisting of hydrogen, methyl and ethyl, the phosphorus-to-lead atom ratioof said composition being from about 0.1:3 to about 1.6:3.

3. The fuel composition of claim 1 in which said cyclic phosphorus compound is 1,3-butylene-(N,N-diethyl)- phosphoramidate.

4. The fuel composition of claim 1 in which said cyclic phosphorous compound is 1,3-butylene-(N,N-dimethyl)- phosphoramidate.

References Cited in the file of this patent UNITED STATES PATENTS 2,340,331 Knutson et a1. Feb. 1, 1944 2,375,218 Fry et a1. May 8, 1945 2,382,622 Toy t Aug. 14, 1945 2,405,560 Campbell Aug. 13, 1946 2,427,173 Withrow Sept. 9, 1947 2,661,365 Gamrath et a1 Dec. '1, 1953 2,661,366 Gamrath et a1. n Dec. 1, 1953 2,765,220 Yust Oct. 2, 1956 2,828,195 Yust et al Mar. 25, 1958 2,839,563 Hechenbleikner June '17, 1958 2,860,958 Gilbert Nov. 18, 1958 2,863,743 Pellegn'ni et a1. Dec. 9, 1958 2,878,255 Toy Mar. .17, 1959 FOREIGN PATENTS 1,094,828 France Dec. 15, 1954 683,405 Great Britain Nov. 26, 1952 OTHER REFERENCES Ind. and Eng. Chem., March 1951, vol. 43, No. 3, tAntiknock Antagonism by Livingston, pp. 663-670. 

1. A HYDROCARBON FUEL OF THE GASOLINE BOILING RANGE ADAPTED FOR USE IN SPARK IGNITION INTERNAL COMBUSTION ENGINES CONTAINING AN ANTIKNOCK QUANTITY OF AN ALKYLLEAD ANTIKNOCK COMPOUND, SAID QUANTITY BEING FROM ABOUT 0.02 TO ABOUT 6.5 GRAMS OF LEAD PER GALLON OF SAID FUEL AND, IN AMOUNT SUFFICIENT TO REDUCE SURFACE IGNITION, A CYCLIC PENTAVALENT PHOSPHORUS COMPOUND HAVING THE GENERAL FORMULA 